GE C70 Instruction Manual page 254

PRODUCT SETUP
The serial communication ports utilize the Modbus protocol, unless the port is configured for DNP or IEC 60870-5-103
operation. This allows the EnerVista UR Setup software to be used on the port. UR devices operate as Modbus slave
devices only.
For more information on the protocol, including the memory map table, see the UR Family Communications Guide.
MODBUS SLAVE ADDRESS
MODBUS SLAVE ADDRESS
from 1 to 254. Address 0 and addresses from 248 and up are reserved by the Modbus protocol specification, and so their
use here is not recommended. Address 0 is the broadcast address to which all Modbus slave devices listen. Addresses do
not have to be sequential, but no two devices can have the same address or conflicts resulting in errors occur. Generally,
starting at 1, set each device added to the link to use the next higher address. When using Modbus TCP/IP, the client must
use the programmed
MODBUS TCP PORT NUMBER
is reserved for Modbus communications, and only in exceptional cases when
port. The
MODBUS TCP PORT NUMBER
0 disables Modbus over TCP/IP, meaning closes the Modbus TCP port. When the port number is changed to 0, the change
takes effect when the C70 is restarted. When it is set to 0, use the front panel or serial port to communicate with the relay.
Do not set more than one protocol to the same TCP/UDP port number, as this results in unreliable operation of
those protocols.
5.3.5.9 Protocol selection
SETTINGS  PRODUCT SETUP  COMMUNICATIONS  PROTOCOL
5
 PROTOCOL

The menu allows selection of one of the following protocols: DNP 3.0, IEC60870-104, or IEC60870-103.
PROTOCOL
— This setting selects the SCADA protocol on which the unit communicates, among DNP3.0, IEC 60870-
SCADA PROTOCOL
104, and IEC 60870-103, with DNP being the default. Options depend on order code. For any change to take effect, restart
the unit.
MMS CONNECTION TIMEOUT
no data traffic on the TCP connection for greater than the time specified by this setting, the connection is terminated. This
frees up the connection to be re-used by a client. A setting of 10 seconds disables this timer. The TCP connection then is
managed by a standard TCP KeepAlive message sequence. These messages are transmitted every 20 seconds when there
is no MMS communication between the relay and the client. If there are no responses to the TCP KeepAlive messages, the
connection is closed. For any change to this setting to take effect, restart the unit. The change takes effect for a new
connection. For any existing open connection when the change is made, close and re-open the connection. Cycling power
to the relay also applies the new setting.
The table shows which of DNP 3.0, IEC 60870-5-104, IEC 60870-5-103, and IEC 61850 protocols are operational on the
RS232, RS485, and Ethernet ports. It shows all possible combinations of the
5-50
— When using the Modbus protocol on the RS232 port, the C70 responds regardless of the
programmed. For the RS485 port, each device on the serial bus must have a unique slave address
value in the Unit Identifier field.
MODBUS SLAVE ADDRESS
— Modbus over TCP/IP can also be used on any of the Ethernet ports. The listening TCP port 502
setting sets the TCP port used by Modbus on Ethernet. A
SCADA PROTOCOL:

DNP 3.0
MMS CONNECTION

TIMEOUT: 120 s
— This setting specifies a time delay for the detection of network TCP connection lost. If there is
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
MODBUS TCP PORT NUMBER
MODBUS TCP PORT NUMBER
Range: DNP 3.0, IEC 60870-5-104, IEC 60870-5-103
Range: 10 to 7200 in steps of 10
and
PROTOCOL DNP CHANNEL 1(2) PORT
is set to any other
of
settings.